


Practical Science

by HRH After Dark (hannahrhen)



Category: The Avengers (Marvel Movies), Thor (Movies)
Genre: Background Bruce, M/M, Masturbation, Nipple Play, Science Bros, Sexy Times, Size Kink, Swearing, Teasing, Voyeurism, weird science
Language: English
Status: Completed
Published: 2013-01-06
Updated: 2013-01-06
Packaged: 2017-11-23 22:59:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,316
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/627446
Author URL: https://archiveofourown.org/users/hannahrhen/pseuds/HRH%20After%20Dark
Summary: <blockquote class="userstuff">
              <p>Tony discovers the Hulk ... pleasuring himself. Everything that happens after that? Purely for science.</p><p>For science, dammit!</p>
            </blockquote>





	Practical Science

**Author's Note:**

> Sometimes you write the story, and sometimes the story writes you. This one wrote the holy hell out of me. Not sorry, but definitely embarrassed. **@warmdarkwoman** : NEVER MENTION THIS TO ME AGAIN, OR YOU LOSE ONE DRINKING BUDDY.
> 
> For anno_Hreog for being the first person to like my Hulksex!fic confession on Tumblr. ;-) And thanks to isahbellah and theoncomingstormcos for the amusing discussion on the [Hulk's dick size](http://hannahrhen.tumblr.com/post/39590858811/i-want-stark-and-by-the-nine-i-shall-have-you) that I'm sure seeded this mess in my head ...

It was the fleeing that tipped Tony off--once the main attack had been thwarted, the regular citizens in the buildings below should have stopped running away from any one particular place.

But the determined flight from a single building gave a good indication of what he’d find inside. JARVIS confirmed it with the familiar life-sign readings.

Bruce, still Hulked out and gone to ground.

They usually left Brucie to his recovery alone, since he only seemed more mortified when he’d come back to himself being watched, even by friends. But the Hulk also had found himself a hidey-hole in a populated area, in a near-condemnation-worthy department store, and Tony, honestly, didn’t feel like cleaning up outside, so ... 

After sending the all-clear to the other Avengers, into the building he went.

Yep, still Hulked, he confirmed, hearing the snorts and grunts coming from around a wall. He stepped over some coats that had exploded out into the impromptu entryway--the fleeing bystanders were probably looters scared off by the Hulk’s presence. (Sometimes Tony wondered if Bruce didn’t plan his post-fight hideouts for this very reason. Bruce never wanted to give the Other Guy that much credit; Tony was more generous to the battlemate who had saved his life more than once, thank you very much.)

Stepping between the purse display and elevators, Tony followed the Hulk’s noises. Too curious for his own good, but also duly cautious, he peeked around the corner, and ...

His jaw actually dropped.

Oh, damn. Bruce.

Wow.

... _Okay._ Tony tried to shake it off. Failed spectacularly.

He would tell Bruce later that the first thing he’d noticed had been the collapsed ceiling, which had deposited the second story’s wares onto the floor of the first. That he’d been concerned that the Hulk was hurt (as if JARVIS wouldn’t have informed him of that immediately).

But Tony was no idiot--and no stranger to things desperate men did when they were alone--so ... yeah, the first thing he’d noticed? The Hulk was masturbating.

Not a dozen feet away from him.

Holy fucking _fuck_.

Okay, yes, apparently the second floor was the furniture department, and maybe there had been some mattresses stacked princess-and-pea-style for some goddamned reason, but, once the ceiling had dropped them in a convenient pile, the Hulk had found himself a soft little nest in which to ... go to town. Proverbially speaking.

And right between the shoes and the Clinique counter, bless him.

Laying back on the overlapping pile of bedding, the Hulk had ripped open what was barely left of his pants, and had himself in a firm grip. Tony felt his eyebrows shoot up toward his hairline. Hulk’s erect dick had to be-- _had to be_ \--at least fifteen inches long and thick enough around that Tony would need at least a second set of hands to ... well, do what Brucie was clearly enjoying doing right now. 

Head thrown back, panting, the Hulk worked his cock with his left hand (interesting, since Bruce was right-handed--Tony filed that away for later consideration). His other hand was pressed between his legs, stroking and hefting his balls. He wasn’t being gentle with himself, but, really, what man is? As he managed a particularly good stroke, Hulk’s foot jerked, driving his heel into the tile floor, spreading cracks that made the surface vibrate, sensation traveling all the way to Tony's lookout.

 _Fuck._ Yeah, he couldn't miss this--he'd never forgive himself. Tony took a step forward from behind the wall, trying to get a better look. After all, he wasn’t likely to get this chance again by, you know, actually _asking_ Bruce, who visibly cringed whenever Tony wondered anything specific about the Other Guy. The Other Guy’s _needs_.

And they’d just been talking about hunger that one time. (Okay, a different kind of hunger.)

The step forward, however, came with the tinny mechanical sound of the suit’s joints realigning, and ... God, he was an idiot. The Hulk’s head shot up, off the mattress pile, and he growled at Iron Man, immediately withdrawing his hand from his own cock and starting to move--to get up. Maybe to kick Tony’s fucking ass for disturbing his private time. Tony knew how he felt when he was interrupted, and he wouldn’t blame Big Green at all.

But ... he held his hands up. “Wait--wait!” The Hulk stilled long enough to give him some hope. He’d been pretty close, from everything Tony knew about jerking off--and he knew _a lot_ \--so he guessed the big guy still had a nice buzz going that he hoped to get back to. “Okay,” he continued, formulating a plan of--uh--attack? “Hang on.” 

Tony pulled off his helmet, set it on the glass top of the nearby counter. He turned back to where the Hulk again lay spread out and _curious_ on the floor, propped over the mattresses and some barely-holding support columns. Tony kept talking as he pulled off more of the suit--gauntlets first. “Look, Big Guy--I’m sorry I interrupted. I am the last guy to cock-block a dude from getting to know his own hand, you know? Sometimes a guy’s just got needs, am I right?”

The Hulk snorted--one of those times Tony suspected Bruce understood a hell of a lot more than he let on. His erection, though flagging, hadn’t completely subsided, and his left hand reached down and gave it an encouraging squeeze. 

“Exactly--that’s all I’m saying.” Tony managed to pop out of the rest of the armor--amazing how quickly he could manage it when he was motivated. “And, while I’m not sure there’s a whole hell of a lot I can do for you without inventing something magnificent--and, Bruce, if you’re in there, I’m gonna start working on it so hard, you have no idea--I would sure as fuck like to watch. And help. If I can.”

The Hulk looked at him dubiously.

Tony added, “For science?”

He knelt next to the Hulk, aching joints happy for the square of mattress. He was flush with the Hulk’s upper thighs, now only slightly spread as the green hand returned to stroking himself--a little hesitantly this time, but it was a good sign anyway. 

“Yep,” Tony repeated. “For science.” He reached a hand out, landing it lightly on the Hulk’s thigh, which was unsurprisingly huge and thick in comparison. Speaking of--

“Christ, Brucie--I mean, I’ve seen you naked, you know, Hulked-out, but I had no idea. I wish we could find you a pretty she-Hulk to try that thing out on.” He glanced up at the Hulk’s face, rethought his position when he realized he was being stared at with ... noticeable interest. “Or, you know, maybe you’d go more for the yang instead of the yin anyway, huh?” He stroked his own hand up and down the giant thigh, registering a gentle exhalation that came from the creature--whether brought about by Tony’s hand or his own. Both. Tony smirked. Probably both.

The Hulk’s unoccupied hand had landed, palm up, next to Tony’s own kneeling figure. Out of the corner of his eye he saw the fingers flex, clench in response to the Hulk’s pleasure.

Absolutely no internal moral debate hamstrung Tony’s mind before he slid his own palm, his own curious fingers, between the Hulk’s legs to tease his balls. Another grunt, and the thighs opened cheerfully, jostling Tony a bit as he shuffled back to make room. The Hulk wasn’t particularly hairy, Tony noticed (see? science!), but his sac was lightly furred with tight black curls, and Tony stroked and teased out one curl just to see it spring back. 

That got a growl. “Sorry, just seeing how things work down here.” He resumed a firmer caress, feeling the testicles beneath the skin slide in his grip, still loose enough to play with, to manipulate, but probably not for long. He moved on his knees farther up the Hulk’s body as his hand kept up the motions, gentle strokes, then more insistent, fingers occasionally dipping behind to tease. As the Hulk kept pulling on his own hot flesh, he let out a moan that sent shivers through Tony’s spine and caused a few fractured panels of glass to fall and crash somewhere else on the floor.

Tony could not give less of a shit about a little broken glass, and he let himself smirk a little, smug in the fact that he was going to have a part in getting the fucking Hulk off, damn it! His smile, and his smugness, died away quickly as the Hulk’s free hand came up to grip Tony’s hip, no doubt to hold him in place. He was pretty sure, after six months of fighting on the same side, that Brucie was in control enough to keep Tony safe even in this, and he hoped to hell he wasn’t wrong. Though he suspected “getting fucked to death by a monstrous cock” had figured prominently both in his enemies’ wishes for him and, frankly--occasionally--in his own late-night frustrated fantasies.

Yeah, he was a sick fuck when he had his fingers up his own ass. So what? As it was right now, he wanted nothing more than to straddle one of those enormous thighs, ride it like mustang until he came, winding the Hulk up even higher ... but ... Yeah, “death by cock” was probably not as exciting as it sounded to his two a.m. pre-orgasm brain. Instead, he rubbed his thumb firmly, repeatedly, over the crease between the Hulk’s testicles, feeling the way they were drawing up to his body. It was enough of a clue that the Hulk was close, as if the grunts and faster pace of his own punishing hand weren’t enough. 

“So, Brucie ... Big Guy,” he started, happily seeing the Hulk’s sex-dazed pupils try to focus on him. “Been wondering ... how sensitive are your nipples? Would you like me to find out? You know, for science?” The hold on his hip tightened--fucking _ow_ , goddammit--but that was enough encouragement. “Oh, good. Because they’re so hard right now, I just need to see what happens if I--” 

He leaned up, ridiculously far considering the usual distance of dick-to-nips, but fortunately it wasn’t so far that he’d have to give up his play with the Hulk’s balls. That would have been a tragedy. His finger and thumb closed over the hockey-puck-sized nipple closest to him, and, without hesitation, he gave it a brutal pinch followed by a slow, soothing roll. 

And _that_ moan? Brought down at least a few more ceiling tiles, as the Hulk’s heels cracked anything solid left of the floor beneath them.

Tony didn’t relent, now that he had his evidence. He continued to twist and roll the tight swell of flesh between his thumb and fingers as his right hand got harder still, less forgiving on the Hulk’s quivering sac. He could see the speed and power the Hulk was using on his own cock--how close he was, his own movements almost a blur. Tony heard the Hulk’s legs twisting on the ground behind him, digging up fragments of ceramic flooring and tearing the edge of one mattress.

In the desperate climb to his own climax, the Hulk uttered just a single word, slow and pained: "Tony ... "

Oh, _Jesus._ Tony was going to need his own goddamned alone time after this. Alone time and a king-sized tube of Astroglide. And a Kleenex factory.

Oh, fuck it--this was Bruce, his buddy, and he deserved this. He kept his focus on the creature--the man below. Giant and green and still Bruce-enough that the huge hand on Tony’s hip, despite the enthusiastic hold, wouldn’t even bruise. Tony’s voice, when it returned, was wrecked, but he knew the Hulk heard and understood every word: “Oh, baby--so close. So close, Brucie--come on. Show me what you can do.”

With that, the Hulk just ... groaned, his own low noise--a rumble that vibrated through the entire building, skittered Tony’s suit pieces on the floor. His arm stilled, hips arced, and ... 

Tony watched avidly as the Hulk shot load after load of shimmery white come onto his own tight abdomen, his own nipples. It was a gorgeous sight, ivory lines on skin flushed jewel-green, and Tony saw it both with the dispassion of a scientist and the horny pride of--yes, fine--a lover. 

He had reluctantly pulled away--one thing Brucie had been adamant about was not touching the Hulk’s bodily fluids without some precaution. Tony lamented it--and highly doubted he was going to catch Mean Green from come, but he also knew the best way to get Bruce to _let him do this again, goddammit,_ was to respect his wishes even when he wasn’t in control.

... _Christ,_ that was a lot of come.

After moments--minutes?--the Hulk had calmed, was playing contentedly with the cooling semen on his stomach, trailing a finger in random patterns. Tony had pressed his hand to his own aching cock, promising it “later, really.” And he simply watched the Hulk in his blissed-out post-orgasmic stupor.

When the green eyes finally returned to meet his own, Tony just offered a smile. “Brucie, that was ... yeah. Thanks for that. The friend in me probably is going to owe you an apology for some damned reason, so let’s just pencil that into the calendar, okay? I-O-U, okay? 

“But, for the record, the Science Bro in me thinks we’re going to have a lot to discuss when you’re back to yourself. Including--and don’t even think about arguing with me--some further stages in this experiment.”

Tony couldn’t help but laugh, however, when the Hulk patted Tony’s hip softly with that giant hand and merely said, in a voice that rumbled through the trashed store: “For ... science.”

**Author's Note:**

> Thanks for reading, y'all! You can find me publicly hand-wringing over my writing, or fangirling over other people's, on Tumblr: <http://hannahrhen.tumblr.com/>


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